<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>第一个简单的jQuery程序</title>
     <script src="https://code.jquery.com/jquery-3.4.1.min.js">
     
     </script>
</head>
<body>
    <div></div>
    <script>
    $(document).ready(
        function(){
            $("div").html("hello Jquert");
        } 
    )
    </script>
</body>
</html>